Precision rail guides known as crossed-roller guides (also called crossed roller slides, linear bearings, or ways) are linear-motion load supports that incorporate arrays of cylindrical roller bearings for the reduction of friction.

Linear slides with crossed-roller arrangements maintain high rigidity. Image courtesy Del-Tron Precision Inc.

These crossed-roller slides contain the rollers between solid twin guide bars (usually made of through-hardened tool steel) cut with V-shaped grooves that are ground to specification. The rollers (often made of hardened roller bearing steel of 55 to 65 HRC) alternate between two 90° offset orientations. Because of this roller orientation, crossed-roller slides can carry loads from four directions.

Crossed-roller bearings don’t exhibit the oscillations and vibrations associated with recirculating bearing balls entering and exiting load zones. This makes for extremely smooth and quiet motion. Installation image courtesy SKF

Usually a third element — a cage — keeps the rollers well-spaced (which in turn prevents excess friction in the form of skidding or poor performance due to roller-to-roller contact) …

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